Bios Cmos Setup; Cmos Ram Map - DIGITAL-LOGIC Microspace MSM586SEN Technical User Manual

DIGITAL-LOGIC AG
5.3.1

BIOS CMOS Setup

If wrong setups are memorized in the CMOS-RAM, the default values will be loaded after resetting the
RTC/CMOS-RAM with the CMOS-RESET jumper. If the battery is down, it is always possible to start the sys-
tem with the default values from the BIOS.
WARNING:
On the next setup pages (switch with TAB) the values for special parameters are modifiable. Normally the
parameters are set correctly by DIGITAL-LOGIC AG. Be very careful in modifying any parameter since the
system could crash. Some parameters are dependent on the CPU type. The cache parameter is always
available, for example. So, if you select too few wait states, the system will not start until you reset the
CMOS-RAM using the RAM-Reset jumper or disoldering the battery, but the default values are reloaded. If
you are not familiar with these parameters, do not change anything!
5.4

CMOS RAM Map

Systems based on the industry-standard specification include a battery backed Real
Time Clock chip. This clock contains at least 64 bytes of non-volatile RAM. The sys-
tem BIOS uses this area to store information including system configuration and ini-
tialization parameters, system diagnostics, and the time and date. This information
remains intact even when the system is powered down.
The BIOS supports 128 bytes of CMOS RAM. This information is accessible through
I/O ports 70h and 71h. CMOS RAM can be divided into several segments:
Locations 00h – 0Fh contain real time clock (RTC) and status information
Locations 10h – 2Fh contain system configuration data
Locations 30h – 3Fh contain System BIOS-specific configuration data as well as chipset-specific in-
formation
Locations 40h – 7Fh contain chipset-specific information as well as power management configura-
tion parameters
The following table provides a summary of how these areas may be further divided.
Beginning Ending
00h 0Fh
10h 2Dh
2Eh 2Fh
30h 33h
34h 3Fh
40h 5Bh
5Ch 5Dh
5Eh 6Eh
6Fh 7Dh
7Eh 7Fh
Checksum Description
No RTC and Checksum
Yes System Configuration
No Checksum Value of 10h – 2Dh
No Standard CMOS
No Standard CMOS – SystemSoft Reserved
Yes Extended CMOS – Chipset Specific
No Checksum Value of 40h – 5Bh
No Extended CMOS – Chipset Specific
Yes Extended CMOS – Power Management
No Checksum Value of 6Fh – 7Dh
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MSM586SEN/SEV Manual V1.5E